Patient GR is a 73-year-old retired
biochemist who has a long-standing history of unilateral keratoconus in his
right eye. He first learned of his condition during a routine military entrance
examination at age 18. Since that time, he had elected to forgo any form of contact lens correction OD and instead relied solely on his left eye for functional vision. GR presented to our clinic interested in a possible contact lens for his right eye because of increasing cataract formation in his left eye.

A Rare Find

We deferred manifest refraction in his right eye because of the advanced nature of the
keratoconus. Manifest refraction in the left eye was ­0.50 ­1.25 x 25 with a visual acuity of 20/30. Simulated keratometric readings were OD 59.50 @ 22/70.50 @ 112 and OS 43.00 @ 180/43.12 @ 90 (Figure 1).

Slit lamp examination OD showed significant apical thinning, typical of an eye in the advanced stage of keratoconus (Figure 2). Perhaps the most notable feature OD was the complete lack of any corneal scarring (Figure 3).

This patient demonstrates two rare findings in severe
keratoconus: 1. a true unilateral manifestation; 2. an advanced form of the condition void of many of the common slit lamp findings such as corneal scarring (ruptures in Bowman's layer), vertical striae and Fleischer's ring.

The bi-aspheric design of the KBA allows the central aspheric portion of the lens to fit with slight apical clearance while the second aspheric zone allows for lens clearance across the flatter midperipheral cornea.